It has the added benefit of being cross-platform. Depending on your project size, consider the complementary tools CPack, CTest, and CDash also by Kitware. (Disclaimer: I don't work for Kitware, but I do help program a project that depends on some of Kitware's products).

I have also heard of some people having great success using Qt's own QMake tool, which should come with the source distribution of Qt.

I'm not sure about most of your post, but one thing I can tell you is that you don't have to update everytime the new version comes out. Wait a little while and you'll probably thank yourself later. It's ok to change versions at home to screw around with it but if you do it commercially it could be a real pain in the butt! Microsoft made me learn this the hard way!

With git, I use git-submodule. This allows me to link to another repository (git, svn, etc) but not save the source to your repository, you just use "git submodule" to pull it. When you push your main repo it doesn't include the submodules. This allows you to keep your local copy, and anyone else can pull the submodules with the submodule command.